function [P]=readobj_vertex(input_file_name)

% input_file_name='mesh/mesh191.obj';
input_file_unit = fopen ( input_file_name, 'r' );
n=0;
while ( 1 )
    text = fgetl ( input_file_unit );
    % %  正则解析 0.433s
    %     S = regexp(text, '\s+', 'split');
    %     if strcmp(S(1),'v')
    %         n=n+1;
    %         P(n,:)=str2double(S(2:end));
    % sscanf解析 0.1s
    %     [str, count] = sscanf(text, '%s')
    if ( text == -1 )
        break;
    else
        A = sscanf(text,'%s %f %f %f');
        if A(1)==118 & A(2)<50
            n=n+1;
            P(n,:)=A(2:4)';
        else
            if n>4
                break;
            end
            continue;
        end
    end
end

fclose ( input_file_unit );





